In LiquidEarth, you can import volumetric data from VTK (.vtk) files. This allows you to bring in results from external modeling tools or simulation workflows and view, analyze, and annotate them directly in your 3D Workspace.

What is VTK?

The VTK file format is a family of formats used to store scientific datasets (grids, meshes, and their associated attributes). In practice, there are three main variants:

1. Legacy VTK (.vtk)

   The original, line-based format can be ASCII or binary. It stores geometry, topology, and data attributes in a single file. It is simple to read and write and is widely supported.

2. XML VTK (.vti, .vtr, .vts, .vtp, .vtu, …)

   A newer, XML-based family of formats with one file extension per dataset type. These support additional features such as better metadata, compression, and parallel I/O via “.pv*” meta-files.

3. VTK-HDF (.vthb, .vti with HDF, etc.)

   An HDF5-backed variant designed for high-performance and large-scale data, combining VTK’s data model with HDF5’s storage and parallel I/O capabilities.

LiquidEarth currently supports only the legacy VTK format.

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For a detailed description, see the official VTK documentation.

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Supported VTK volume grids in LiquidEarth

LiquidEarth supports the following legacy VTK volume grid types:

• File format: ASCII or BINARY

• VTK dataset types (geometry):

  • RECTILINEAR_GRID

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  Internally, these datasets are treated as uniform, axis-aligned voxel grids based on their dimensions. Non-uniform rectilinear spacing is not currently preserved; only the logical (i, j, k) structure and cell-centered scalar values are used.

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• Supported attribute association: CELL_DATA

• Supported attribute types in CELL_DATA:

  • Single-component SCALARS
  • Single-component FIELD arrays

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  Multi-component cell attributes such as VECTORS, TENSORS, COLOR_SCALARS, or multi-component FIELD arrays are not supported at the moment.

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• File extension: .vtk

Example VTK File

Use this example to get familiar with the import workflow or compare its data structure with a file you plan to import.

• Example - Cube using rectilinear grid

  • File:

    example_rg_cube.vtk

    # vtk DataFile Version 3.0
    5x5x5 rectilinear cube with per-layer attribute (25 scalars/line)
    ASCII
    DATASET RECTILINEAR_GRID
    DIMENSIONS 6 6 6
    X_COORDINATES 6 float
    0.0 1.0 2.0 3.0 4.0 5.0
    Y_COORDINATES 6 float
    0.0 1.0 2.0 3.0 4.0 5.0
    Z_COORDINATES 6 float
    0.0 1.0 2.0 3.0 4.0 5.0
    CELL_DATA 125
    SCALARS attribute int 1
    LOOKUP_TABLE default
    0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
    1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
    2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
    3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
    4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4
    

  • Download:

    example_rg_cube.vtk

    example_rg_cube.vtk

  • Description:

    This is a simple example of a 5x5x5 cube that has a per-layer attribute using RECTILINEAR_GRID. The attribute name is attribute.

Importing in LiquidEarth